An Anionic Surfactant Metallomicelle: Catalytic Activity and Mechanism for the Catalytic Hydrolysis of a Phosphate Ester

Abstract

An aza-crown ether ligand was synthesised and characterised. The chemical composition of the binary complex containing cerium(III) and the ligand was determined by fluorescence spectroscopy. A new metallomicellar system comprising the cerium(III) complex of the ligand and an anionic micelle (n-lauroylsarcosine) was used as catalyst in the hydrolysis of bis(4-nitrophenyl) phosphate ester (BNPP). The catalytic rate of BNPP hydrolysis and the local concentration effect of the micelle were measured kinetically using UV-Vis spectrophotometry. The results indicated, that compared with a cationic metallomicelle system made from the aza-crown ether, lanthanum(III) ion and CTAB cationic surfactant in our previous report, the anionic metallomicelle exhibited a six-fold higher catalytic activity in BNPP hydrolysis at neutral pH and the same other conditions, thus the micelle based on LSS provides a more effective catalytic environment for reaction. A reaction mechanism has been proposed.